str1 = 'this is a test'
str2 = "THIS IS A TEST"

if str1.isupper():
    print(f"{str1}: 是大写")
if str2.isupper():
    print(f"{str2}: 是大写")

if str1.islower():
    print(f"{str1}: 是小写")
if str2.islower():
    print(f"{str2}: 是小写")

'''
THIS IS A TEST: 是大写
this is a test: 是小写
'''

# 每个单词-首字母大写判断
str3 = "This Is A Test"
if str3.istitle():
    print(f"{str3}: 首字母大写")
'''
This Is A Test: 首字母大写
'''